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HOMEMADE compass for drawing circles

It's very nice ... I just wanted to say in my opinion you can't go wrong with the flange wizard radius markers they are made in USA and good quality..... I was in a pinch once I had to cut a circle that was 12' 0" in so I just cut a piece of and tacked a center punch on one end and a soapstone holder on the other end had my helper hold the point in the the center punch hole and I carefully went around in a circle ... Cutting that ******* was the hard part it was 1" plate so I had to freehand it with a torch .... It worked but I had my helper using a rosebud ahead of me preheating

An excellent design and a big improvement on what can be purchased in the
average shop.

if you have the time and inclination to build these tools that's fine but this has all been done before. you can buy starrett sheet metal worker's calipers and substitute a pencil by removing a leg. (pencil may need a little sanding) they come in different sizes.

when i was specifically a layout person i had several dividers of different sizes and a pair of sheet metal worker's calipers, and often i would use my six inch dial calipers to strike arcs/circles. i also kept three sets of trammel points for striking large arcs. (trammel points will accept beams of different sizes) the general's were good because you could substitute a pencil for one of your points.

frequently when laying out cones or conical sections where the apex was a good distance we would use a stringline and a trammel point to layout the arc.

these tools, specifically the starrett calipers are expensive today but i'm sure, though i haven't looked, you can buy imports.

then, around 1982 i picked up a TI scientific calculator and using simple linear equations found that i could solve many of these problems at the bench without the need of large graphical, projected view solutions to determine the true length of lines; it was obvious to me then that things were about to radically change; and they did.

i see these little projects and can't help but appreciate the irony that on one level we are moving ahead and on another we are going backwards.

to the guy above that had his helper preheating the plate, they do make cutting tips of different sizes for cutting different thicknesses. that must have looked strange.

HOMEMADE compass for drawing circles

Ok bub .... Don't get all professor on me .. I totally understand cutting tips and there purposes.... I own hundreds from tiny oooo1 to a number six that I have never used ... The plate I cut was only one inch plate ... I could have used a number 1 or 2 I don't remember I'm sure I used a two ... I do remember it had a bunch of milll scale ..... I don't know or care where you work or have worked or your skill level but I betcha my method of using a rosebud ahead preheating has been done in the past and will be done again buy lots of journeyman fabricators ... I work in Alaska we don't use a bunch of of high tech stuff my shop puts out lots of oilfield service piping equipment and tanks you name it we use track torches or plazma cutters or hand torches , slugger drills we don't use punches iron workers c and c machines sub arc or wire .. We burn rod like welders were not technicions we don't use anything else that puts welders and fitters on the bench we do it the old way it works just fine